Multi-objective robust controller design for spacecraft hovering around elliptical orbital target

Abstract

This research investigates the state-feedback control approach for spacecraft hovering around elliptical orbital target. An uncertain hovering model subject to parameter uncertainties and exogenous disturbances is used to describe the relative motion of two spacecraft. The process of spacecraft hovering is divided into two steps: orbital transfer control and hovering maintenance control. A bi-objective robust controller design algorithm is presented for the orbital transfer, in which fuel optimization and pole placement are taken into account. And then, we derive sufficient conditions for the multi-objective robust hovering maintenance control considering H2 performance, H∞ performance and pole placement. By applying Lyapunov approach, the controller design problems are transferred into convex optimization problems subject to linear matrix inequality constraints. Numerical simulations illustrate the effectiveness of the proposed control laws for orbital transfer and hovering maintenance. The orbital transfer process can be achieved with continuous thrust with an upper bound of fuel consumption. The obtained hovering maintenance controller can handle parameter uncertainties and exogenous disturbances effectively, and the accuracy of relative position meets the demand of spacecraft hovering.